1. Field of the Invention
The present invention relates to a printing device such as a copying machine, a Multi Function Peripheral (MFP) having multiple functions such as a copy function and a facsimile function and a printer device. In particular, the present invention relates to a printing device with a manual paper feeding function.
2. Description of Related Art
A conventional printing device such as a copying machine includes a paper cassette and also a manual paper feeding unit. There are cases in which the printing device carries out a copying process by a manual paper feeding operation. In such a type of printing device with a manual paper feeding operation, to carry out a copying (printing) process onto paper fed from the manual paper feeding unit, in case the manual paper feeding operation is a multiple manual feeding operation, when a paper size recognized by the printing device is different from a paper size of the paper actually set in the manual paper feeding unit, a paper size error is displayed to urge the user to set a correct paper size. Meanwhile, in case the manual paper feeding operation is a single manual feeding, when the paper size recognized by the printing device is different from the paper size of the paper actually set in the manual paper feeding unit, the paper size error is ignored and the copying process is carried out.
A conventional printing device includes a first printing mode and a second printing mode. Under the first printing mode, a paper size of paper set on a manual paper feeding unit is designated from outside and a printing sequence is carried out in accordance with the designated paper size. Under the second printing mode, without designating the paper size from outside, the printer device measures the paper size and a printing sequence is carried out in accordance with the measured paper size. After the paper size is designated from outside, when the paper set on the manual paper feeding unit runs out, the printing device switches once to a size measuring mode. After the paper size is measured, the printing device switches to an appropriate paper size mode.
When carrying out the copying process onto the paper fed from the manual paper feeding unit, the paper size is detected. When the detected paper size corresponds with the paper size previously recognized by the printing device, papers are fed sequentially from the manual paper feeding unit to a printer unit at an interval corresponding to the detected paper size. That is, a printing sequence is carried out in accordance with the detected paper size. However, there are cases in which the paper size cannot be detected. For example, when the paper size is a nonstandard size, the paper size cannot be detected. In case a printing sequence of A4 size papers is in progress and the papers are fed sequentially at an interval corresponding to the A4 size papers, when nonstandard sized paper larger than the A4 size paper is fed during the printing sequence, a paper size error is displayed to urge the user to set the correct paper again. Therefore, even when the printing process can be continued with the nonstandard sized paper, the printing process is interrupted. As a result, there is a drawback of a decrease in printing efficiency which causes the user to feel troublesome. In case the paper size is unknown, the conventional printing device cannot deal with the drawback.